Battery operated devices, such as power tools, appliances, computers, etc., are common place in today's households, offices and work sites. A large percentage of the batteries used to power such devices are constructed as multi-cell battery packs, such as multi-cell NiCd, NiMh or Lithium Ion battery packs. The ever increasing utilization of multi-cell battery packs to power such devices has been accompanied by a demand for increased battery power, extended battery life, and longer battery durability. To achieve increased power, extended life, and longer durability, it is important that the battery packs not be charged significantly above or discharged below a normal charge range for the respective battery. More specifically, it is important that no cell within the respective battery pack be charged significantly above or discharged below a normal charge range for the battery pack.
Ideally, each of the cells within a battery pack will have similar charging, discharging and efficiency characteristics. However, this ideal scenario is not easily achieved and often each battery cell within a battery pack can have different charging, discharging and efficiency characteristics. Such differences in cell characteristics can complicate the issue of overcharging and undercharging of a battery pack, i.e., overcharging and undercharging the cells of a battery pack. For instance, fully charging one battery cell in a battery pack can result in overcharging one or more of the other battery cells in the battery pack. Likewise, ending a charge cycle when only one battery cell is fully charged can result in undercharging one or more of the other battery cells in the battery pack.
The statements in this section merely provide background information related to the present disclosure and can not constitute prior art.